As an important component part-optical module in the existing optical communication industry, its production capacity is increasing, its process and control technology become more and more complicated. With the diversification of business, optical communication system providers put forward higher requirements to optical module manufacturers. The system providers also particularly concern about the in-application upgrade technology of the optical module firmware in this context. For example, if an online upgrade technology is not used in the existing optical module, the system providers will do performance adjustment of the optical module, or if design flaws are found in the optical module firmware, the usual practice is that the optical module manufacturers recall the optical modules and use a professional download tool to re-download the firmware after opening its shell, which not only consumes a lot of manpower and transportation costs, but also easily causes damage to the optical module. Currently, the control parts of the relatively high side optical module are mostly achieved on the basis of an ARM-core MCU (Micro Control Unit). Some well-known MCU manufacturers at home and abroad also provide in-application upgrade technology (IAP) of the MCU firmware, but the in-application upgrade technology applied in the field of the optical module still has certain obvious deficiencies, of which the biggest problem is that the reset operation of the MCU is required for the firmware provided by the MCU manufacturers in the updated scheme of application before or after upgrading the firmware without exception. In this way, the service of the optical module in the normal communication is broken to cause unpredictable risk for the operators. Meanwhile, the in-application upgrade technology provided by the majority of MCU manufacturers downloads and updates the firmware with a serial port or a network interface, which is also unacceptable for the smaller optical module.